Buggy code:
public class ParentSignUp extends AppCompatActivity { public static final String PARENT_SIGNUP_URL = "http:////10.1.0.244//tryme//register.php" ; private Button parentSignUp ; private EditText editTextUsername ; private EditText editTextFamilytName ; private EditText editTextEmail ; private EditText editTextPassword ; private TextView txtLoginSignup ; ProgressDialog PD ; @ Override protected void onCreate ( Bundle savedInstanceState ) { } private void parentSignUP ( ) { PD . show ( ) ; final String username = editTextUsername . getText ( ) . toString ( ) . trim ( ) ; final String familyName = editTextFamilytName . getText ( ) . toString ( ) . trim ( ) ; final String email = editTextEmail . getText ( ) . toString ( ) . trim ( ) ; final String password = editTextPassword . getText ( ) . toString ( ) . trim ( ) ; if ( ( username . length ( ) ) < 4 ) { PD . dismiss ( ) ; editTextUsername . setError ( "Invalid<seq2seq4repair_space>Username" ) ; } else if ( ( familyName . length ( ) ) < 4 ) { PD . dismiss ( ) ; editTextFamilytName . setError ( "Invalid<seq2seq4repair_space>Family<seq2seq4repair_space>Name" ) ; } else if ( ! ( isValidEmail ( email ) ) ) { PD . dismiss ( ) ; editTextEmail . setError ( "Invalid<seq2seq4repair_space>Email" ) ; } else if ( ! ( isValidPassword ( password ) ) ) { PD . dismiss ( ) ; editTextPassword . setError ( ( "Must<seq2seq4repair_space>be<seq2seq4repair_space>at<seq2seq4repair_space>least<seq2seq4repair_space>6<seq2seq4repair_space>characters<seq2seq4repair_space>long" + ( ( ( ( ( "\n" + "Must<seq2seq4repair_space>contain<seq2seq4repair_space>upper<seq2seq4repair_space>&<seq2seq4repair_space>lower<seq2seq4repair_space>case" ) + "\n" ) + "Must<seq2seq4repair_space>contain<seq2seq4repair_space>number" ) + "\n" ) + "Must<seq2seq4repair_space>contain<seq2seq4repair_space>special<seq2seq4repair_space>character" ) ) ) ; } else { StringRequest stringRequest = new StringRequest ( Method . POST , ParentSignUp . PARENT_SIGNUP_URL , new Response . Listener < String > ( ) { @ Override public void onResponse ( String response ) { PD . dismiss ( ) ; <START_BUG> if ( response . equals ( "Successfully<seq2seq4repair_space>Registered" ) ) { <END_BUG> successfulParentRegistered ( ) ; Log . e ( "You<seq2seq4repair_space>are" , response ) ; } } } , new Response . ErrorListener ( ) { @ Override public void onErrorResponse ( VolleyError error ) { PD . dismiss ( ) ; Log . e ( "Error<seq2seq4repair_space>::<seq2seq4repair_space>" , error . toString ( ) ) ; Toast . makeText ( ParentSignUp . this , error . toString ( ) , LENGTH_SHORT ) . show ( ) ; NetworkResponse networkResponse = error . networkResponse ; if ( networkResponse != null ) { Log . e ( "Volley" , ( "Error.<seq2seq4repair_space>HTTP<seq2seq4repair_space>Status<seq2seq4repair_space>Code:" + ( networkResponse . statusCode ) ) ) ; } if ( error instanceof TimeoutError ) { Log . e ( "Volley" , "TimeoutError" ) ; } else if ( error instanceof NoConnectionError ) { Log . e ( "Volley" , "NoConnectionError" ) ; } else if ( error instanceof AuthFailureError ) { Log . e ( "Volley" , "AuthFailureError" ) ; } else if ( error instanceof ServerError ) { Log . e ( "Volley" , "ServerError" ) ; } else if ( error instanceof NetworkError ) { Log . e ( "Volley" , "NetworkError" ) ; } else if ( error instanceof ParseError ) { Log . e ( "Volley" , "ParseError" ) ; } } } ) { @ Override protected Map < String , String > getParams ( ) throws AuthFailureError { Map < String , String > params = new HashMap < String , String > ( ) ; params . put ( "userName" , username ) ; params . put ( "familyName" , familyName ) ; params . put ( "email" , email ) ; params . put ( "password" , password ) ; return params ; } } ; int socketTimeout = 30000 ; RetryPolicy policy = new DefaultRetryPolicy ( socketTimeout , DefaultRetryPolicy . DEFAULT_MAX_RETRIES , DefaultRetryPolicy . DEFAULT_BACKOFF_MULT ) ; stringRequest . setRetryPolicy ( policy ) ; RequestQueue requestQueue = Volley . newRequestQueue ( this ) ; requestQueue . add ( stringRequest ) ; } } public void successfulParentRegistered ( ) { } private boolean isValidEmail ( String email ) { } private boolean isValidPassword ( String password ) { } }

Fix:
if ( response . equals ( "successfully" ) ) {